There is a great variety of toys capable of movement; among these, toys which imitate animals' way of walking are also very common. The driving mechanism of these toys (including mechanical animals) consists of a main shaft driving the two feet of the toy animal to move forward and backward alternately, and therefore, the body of the toy appears stiff and dull due to inaction. Besides, the length of the feet of the toy animal is fixed and unchanged, so that when the feet move along the floor, because of the frictional force thus generated, the walking speed of the toy is very slow.
For a toy animal with a tail, such as the dinosaur, the conventional driving device has to further overcome the frictional resistance produced when the tail drags along the floor.
How to eliminate the frictional resistance when toy animals with tails walk along the floor; how to make the step of the toy animal longer; and how to make the body of the toy animal twist more realistically when walking; all these problems point to the direction which manufacturers of toys imitating the walking movement of animals should follow in seeking breakthroughs in conventional designs.